Touch sensor and display device

ABSTRACT

Disclosed is a touch sensor including a first layer, a second layer over the first layer, and a third layer over the second layer. The first layer has a plurality of first insulators arranged in a stripe form and extending in a first direction, and a plurality of first wirings arranged in a stripe form and extending in a second direction intersecting with the first direction. The second layer includes an insulating material. The third layer has a plurality of second insulators arranged in a stripe form and extending in the second direction, and a plurality of second wirings arranged in a stripe form and extending in the first direction. The plurality of first insulators and the plurality of the first wirings are woven with each other, and the plurality of second insulators and the plurality of the second wirings are woven with each other.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority from theprior Japanese Patent Application No. 2016-141295, filed on Jul. 19,2016, the entire contents of which are incorporated herein by reference.

FIELD

An embodiment of the present invention relates to a touch sensor and amanufacturing method thereof or a display device on which a touch sensoris mounted and a manufacturing method thereof.

BACKGROUND

A touch sensor has been known as an interface for a user to inputinformation to a display device. Provision of a touch sensor on adisplay device allows a user to directly operate input buttons and iconsdisplayed on a screen, by which information can be readily input to anelectronic device through a display device. For example, in JapanesePatent Application Publications No. 2015-18331, No. 2015-50245, and No.2010-85378, a display device to which a touch sensor is installed on adisplay panel having light-emitting elements utilizingelectroluminescence is disclosed. Japanese Patent ApplicationPublication No. 2015-18331 discloses a touch sensor having a structurein which a plurality of wirings intersecting with each other isinterwoven.

SUMMARY

An embodiment of the present invention is a touch sensor including afirst layer, a second layer over the first layer, and a third layer overthe second layer. The first layer has a plurality of first insulatorsarranged in a stripe form and extending in a first direction, and aplurality of first wirings arranged in a stripe form and extending in asecond direction intersecting with the first direction. The second layerincludes an insulating material. The third layer has a plurality ofsecond insulators arranged in a stripe form and extending in the seconddirection, and a plurality of second wirings arranged in a stripe formand extending in the first direction. The plurality of first insulatorsand the plurality of the first wirings are woven with each other, andthe plurality of second insulators and the plurality of the secondwirings are woven with each other.

An embodiment of the present invention is a touch sensor including aplurality of first wirings arranged in a stripe form and extending in afirst direction, and a plurality of second wirings arranged in a stripeform and extending in a second direction intersecting with the firstdirection. The plurality of first wirings and the plurality of secondwirings are woven with each other. The plurality of first wirings andthe plurality of the second wirings each possess a core including aconductive material and a clad covering the core and including aninsulating material.

An embodiment of the present invention is a touch sensor including: aplurality of first wirings arranged in a stripe form and extending in afirst direction; and a plurality of second wirings and a plurality ofthird wirings arranged in a stripe form, extending in a second directionintersecting with the first direction, and alternating with each other.The plurality of first wirings is woven with the plurality of secondwirings and the plurality of third wirings. The plurality of firstwirings and the plurality of second wirings each have a first coreincluding a conductive material and a first clad covering the first coreand including an insulating material. The plurality of third wiringspossesses a second core including a conductive material, a second cladcovering the second core and including an insulating material, and athird clad covering the second clad and including a conductive material.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic perspective view of a display device according toan embodiment of the present invention;

FIG. 2A and FIG. 2B are respectively a schematic top view andcross-sectional view of a touch sensor according to an embodiment of thepresent invention;

FIG. 3A to FIG. 3C are schematic developed views of a touch sensoraccording to an embodiment of the present invention;

FIG. 4 is a drawing for explaining an operation mechanism of a touchsensor according to an embodiment of the present invention;

FIG. 5A and FIG. 5B are schematic developed views of a touch sensoraccording to an embodiment of the present invention;

FIG. 6A and FIG. 6B are schematic developed views of a touch sensoraccording to an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a display device accordingto an embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a display panel of adisplay device according to an embodiment of the present invention;

FIG. 9A and FIG. 9B are respectively a schematic top view andcross-sectional view of a touch sensor according to an embodiment of thepresent invention;

FIG. 10 is a schematic cross-sectional view of a wiring of a touchsensor according to an embodiment of the present invention;

FIG. 11 is a schematic top view of a touch sensor according to anembodiment of the present invention;

FIG. 12A to FIG. 12C are schematic cross-sectional views of a touchsensor according to an embodiment of the present invention;

FIG. 13 is a schematic cross-sectional view of a wiring of a touchsensor according to an embodiment of the present invention;

FIG. 14 is a drawing for explaining an operation mechanism of a touchsensor according to an embodiment of the present invention;

FIG. 15A and FIG. 15B are drawings for explaining an operation mechanismof a touch sensor according to an embodiment of the present invention;

FIG. 16 is a schematic top view of a touch sensor according to anembodiment of the present invention;

FIG. 17A to FIG. 17C are schematic developed views of a touch sensoraccording to an embodiment of the present invention;

FIG. 18A and FIG. 18B are respectively schematic cross-sectional viewsof a touch sensor and a wiring according to an embodiment of the presentinvention;

FIG. 19 is a schematic cross-sectional view of a touch sensor accordingto an embodiment of the present invention;

FIG. 20A to FIG. 20C are schematic cross-sectional views for explaininga manufacturing method of a display panel of a display device accordingto an embodiment of the present invention;

FIG. 21A and FIG. 21B are schematic cross-sectional views for explaininga manufacturing method of a display panel of a display device accordingto an embodiment of the present invention; and

FIG. 22A and FIG. 22B are schematic cross-sectional views for explaininga manufacturing method of a display panel of a display device accordingto an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the embodiments of the present invention are explained withreference to the drawings. The invention can be implemented in a varietyof different modes within its concept and should not be interpreted onlywithin the disclosure of the embodiments exemplified below.

The drawings may be illustrated so that the width, thickness, shape, andthe like are illustrated more schematically compared with those of theactual modes in order to provide a clearer explanation. However, theyare only an example, and do not limit the interpretation of theinvention. In the specification and the drawings, the same referencenumber is provided to an element that is the same as that which appearsin preceding drawings, and a detailed explanation may be omitted asappropriate.

In the present invention, when a plurality of films is formed byprocessing one film, the plurality of films may have functions or rulesdifferent from each other. However, the plurality of films originatesfrom a film which is formed as the same layer in the same process.Therefore, the plurality of films is defined as films existing in thesame layer.

In the specification and the scope of the claims, unless specificallystated, when a state is expressed where a structure is arranged “over”another structure, such an expression includes both a case where thesubstrate is arranged immediately above the “other structure” so as tobe in contact with the “other structure” and a case where the structureis arranged over the “other structure” with an additional structuretherebetween.

First Embodiment

In the present embodiment, a structure of a display device 100 accordingto an embodiment of the present invention is explained by using FIG. 1to FIG. 8.

1. Outline Structure

The display device 100 has a touch sensor 200 and a display panel 300arranged over the touch sensor 200. In FIG. 1, a state is shown wherethe touch sensor 200 and the display panel 300 are separated. However,the touch sensor 200 and the display panel 300 are bonded with anadhesive and the like. The display panel 300 reproduces an image, andthe touch sensor 200 has a function to specify a contact position when auser makes contact to the display 300 and estimate physical forceprovided to the display device 200 from a user when contacted.

The touch sensor 200 has a sensing region 204 and driver circuits 206and 208 for driving the sensing region 204 in a peripheral region of thesensing region 204. The driver circuits 206 and 208 have a function tosupply signals to a variety of wirings described below in the sensingregion 204 or a function to sense variation in voltage applied to thevariety of wirings and current flowing in the variety of wirings. Asubstrate 202 is an optional structure, and the sensing region 204 andthe driver circuits 206 and 208 may be formed over the substrate 202.The substrate 202 is able to support the sensing region 204 and thedisplay panel 300 and may include glass, plastics, a metal, or the like,for example. The substrate 202 may possess flexibility. In this case,the substrate 202 may include a polymer such as a polyimide, apolyester, and a polycarbonate. The driver circuits 206 and 208 are notlimited in number and may be disposed at each of four sides of thesensing region 204 or on a substrate different from the substrate 202.

The display panel 300 has an array substrate 302 and an opposingsubstrate 304 over the array substrate 302, and a display region 306 isprovided therebetween. As described below in detail, the display region306 is provided with a plurality of pixels 308 including a displayelement and a semiconductor element for driving the display element,such as a transistor. An image is reproduced on the display region 306with the plurality of pixels 308. Driver circuits 310 and 312 may bedisposed between the array substrate 302 and the opposing substrate 304in order to control the pixels 308. Alternatively, the driver circuits310 and 312 may not be provided between the array substrate 302 and theopposing substrate 304 but may be arranged over a connector (notillustrated) for connecting the display panel 300 to an externalcircuit.

The touch sensor 200 and the display panel 300 overlap with each other,by which the sensing region 204 and the display region 306 are arrangedso as to overlap with each other. Therefore, when a user touches theopposing substrate 304 or provides force to the opposing substrate 304while recognizing an image reproduced in the display region 306, theforce is conveyed to the sensing region 204, by which a contact positionof the user is specified and the force provided by the user isestimated.

2. Touch Sensor

A schematic top view and cross-sectional view of the touch sensor 200are shown in FIG. 2A and FIG. 2B, respectively. FIG. 2B corresponds to across section along a chain line A-A′ of FIG. 2A.

As shown in FIG. 2B, the touch sensor 200 possesses a first layer 220, asecond layer 230 over the first layer 220, and a third layer 240 overthe second layer 230. In order to promote understanding, only the secondlayer 230 and the third layer 240 are illustrated in FIG. 2A. The firstlayer 220, the second layer 230, and the third layer 240 overlap withone another.

Top views of the first layer 220, the second layer 230, and the thirdlayer 240 obtained by developing the touch sensor 200 are schematicallyillustrated in FIG. 3A, FIG. 3B, and FIG. 3C, respectively. As shown inFIG. 2B and FIG. 3A, the first layer 220 has a plurality of firstinsulators 222 arranged in a stripe form and a plurality of firstwirings 224 arranged in a stripe form. The first insulators 222 and thefirst wirings 224 may be in contact with each other. The firstinsulators 222 extend in a direction (first direction), while the firstwirings 224 extend in a direction (second direction) perpendicular tothe first direction. The first direction and the second direction maynot be perpendicular to each other as long as they intersect with eachother. The first insulators 222 and the first wirings 224 are woven witheach other and serve as warp and weft, respectively. In the presentspecification, the warp and the weft interchange with each otherdepending on a direction of the touch sensor 200 to a user. Thus, theexpression of the warp and the weft is merely used for convenience. Thefirst insulators 222 and the first wirings 224 may have a structure inwhich they are plain-woven as shown in FIG. 3A. In this case, the firstinsulators 222 and the first wirings 224 alternately intersect with eachother. In other words, the first insulators 222 each alternately passover and under the plurality of first wirings, and the first wirings 224each alternately pass over and under the plurality of first insulators222.

The first insulators 222 include an insulating material. An insulatingmaterial may be an organic compound or an inorganic compound. An organiccompound can be selected from an artificial polymer or a naturalpolymer. These polymers may be crosslinked intermolecularly orintramolecularly. As an artificial polymer, a polymer having apolyurethane, a polyolefin, a polydiene, a poly(acrylic ester), apoly(methacrylic ester), a polyacrylonitrile, a polysiloxane, apolyester, a polycarbonate, or the like as a basic skeleton isrepresented. As a natural polymer, natural rubber, plant fiber such ascotton and hemp, animal fiber such as wool and silk, or fiber obtainedby processing these fibers is given. As an inorganic compound, glassfiber, rock-wool fiber, ceramic fiber, or fiber including atransition-metal oxide, such as potassium titanate fiber, isexemplified.

The first wirings 224 include a conductive material represented by ametal such as copper, aluminum, silver, titanium, iron, and the like, analloy thereof, a conductive oxide, carbon fiber, and the like.Alternatively, the aforementioned insulating material may be coveredwith a conductive material.

These materials are woven as warp and weft and processed to a sheetshape, leading to the formation of the first layer 220.

The second layer 230 is formed over the first layer 220. The secondlayer 230 may be in contact with the first insulators 222 and the firstwirings 224. The second layer 230 includes an insulating material, and amaterial usable for the first insulators 222 can be used. The insulatingmaterial of the second layer 230 may be different from that of the firstinsulators 222. In this case, the second layer 230 may be processed intoa sheet shape, and then disposed over the first layer 220 with alamination method and the like. Alternatively, the second layer 230 maybe formed over the first layer 220 with a wet-type film-formation methodsuch as a spin-coating method and a printing method.

Alternatively, the second layer 230 may include a silicon-containinginorganic compound such as silicon oxide, silicon nitride, siliconoxynitride, and silicon nitride oxide. In addition, a metal oxide oftitanium, hafnium, and the like may be used. The second layer 230including these materials can be formed with a sputtering method, achemical vapor deposition method (CVD method), and the like.

The third layer 240 may have a similar structure to that of the firstlayer 220. Specifically, as shown in FIG. 2A, FIG. 2B, and FIG. 3C, thethird layer 240 possesses a plurality of second wirings 242 arranged ina stripe form and a plurality of second insulators 244 arranged in astripe form. The second wirings 242 and the second insulators 244 may bein contact with each other. The second wirings 242 extend in the firstdirection, whereas the second insulators 244 extend in the seconddirection. Thus, the plurality of first wirings 224 and the plurality ofsecond wirings 244 perpendicularly intersect with each other with thesecond layer 230 sandwiched therebetween. The second wirings 242 and thesecond insulators 244 are woven with each other and serve as warp andweft, respectively. As shown in FIG. 3C, the second wirings 242 and thesecond insulators 244 may have a structure in which they areplain-woven. In this case, similar to the first layer 220, the secondwirings 242 and the second insulators 244 alternately intersect witheach other. That is, the second insulators 244 each alternately passover and under the plurality of second wirings 242, and the secondwirings 242 each alternately pass over and under the plurality ofinsulators 244.

The second wirings 242 and the second insulators 244 may contain thematerials of the first wirings 244 and the first insulators 222,respectively.

A drawing illustrating only the first wirings 244 and the second wirings242 is shown in FIG. 4. As described above, the first wirings 224 andthe second wirings 242 perpendicularly intersect with each other withthe second layer 230 sandwiched therebetween. Hence, the second layer230 functions as a dielectric, and a capacitance 250 is generatedbetween the first wirings 224 and the second wirings 242. When analternating voltage (pulse voltage) is applied to one of the pluralityof first wirings 224 and the plurality of second wirings 242 in atime-division manner, a potential of the other one is changed due tocoupling of the capacitance 250. A magnitude of this change is sensed todetect the absence or presence of a touch at certain coordinates. Forexample, when an alternative voltage is applied to the plurality offirst wirings 224 and a user directly or indirectly contacts the touchsensor 200 (hereinafter, this operation is referred to as a touch),capacitance is newly added between the first wirings 224 and the user.As a result, the coupling between the first wirings 224 and the secondwirings 242 is partly impeded, resulting in a decrease in amplitude ofthe voltage of the second wirings 242. Detection of this decrease inamplitude enables recognition of a touch of a user, by which a positionof the touch can be specified. Therefore, the touch sensor 200 functionsas a capacitive-type (projective-capacitive type) touch sensor.

The weaving mode of the plurality of first insulators 222 and theplurality of first wirings 224 is not limited to a plain weave. Forexample, as shown in FIG. 5A, plurality of first insulators 222 and theplurality of first wirings 224 may be twilled. In this case, the firstinsulators 222 each pass over one first wiring 224, successively passunder two adjacent first wirings 242, and then repeat this sequence. Onthe other hand, the first wirings 224 each pass under one firstinsulator 222, successively pass over two adjacent first insulators 222,and then repeat this sequence.

Similarly, the weaving mode of the second wirings 242 and the secondinsulators 244 may be twilled as shown in FIG. 5B, for example. In thiscase, the second insulators 244 each pass under one second wiring 242,successively pass over two adjacent second wirings 242, and then repeatthis sequence. On the contrary, the second wirings 242 pass over onesecond insulator 244, successively pass under two adjacent secondinsulators 244, and then repeat this sequence. The application of thetwilled structure suppresses generation of a wrinkle in the first layer220 and the third layer 240, facilitating formation of the touch sensor200.

Furthermore, as shown in FIG. 6A, the plurality of first insulators 222and the plurality of first wirings 224 may be satin-woven. Similarly,the plurality of second insulators 244 and the plurality of secondwirings 242 may be satin-woven (see, FIG. 6B). In this case, in thefirst layer 220, the first insulators 222 each pass over one firstwiring 224, successively pass under four first wirings 224, and thenrepeat this sequence. On the contrary, the first wirings 224 each passunder one first insulator 222, successively pass over four firstinsulators 222, and then repeat this sequence. In the third layer 240,the second insulators 244 each pass under one second wiring 242,successively pass over four second wirings 242, and then repeat thissequence. On the other hand, the second wirings 242 each pass over onesecond insulator 242, successively pass under four second insulators244, and then repeat this sequence. The use of the satin-woven structureenables a reduction of projections and depressions at a surface of thetouch sensor 200.

The first layer 220 and the third layer 240 may have different weavingmodes from each other. For example, the first insulators 222 and thefirst wirings 224 may be plain-woven in the first layer 220, and thesecond insulators 244 and the second wirings 242 may be twilled orsatin-woven in the second layer 230.

The touch sensor 200 and the display panel 300 are adhered to each otherwith an adhesion layer 252 to give the display device 100. For instance,as shown in FIG. 7, the adhesion layer 252 is provided so as to coverthe touch sensor 200, and the array substrate 302 of the display panel300 is disposed thereover. At this time, the third layer 240 may be incontact with the array substrate 302 although not illustrated. Namely,the second insulators 244 and the second wirings 242 may be in contactwith the array substrate 302. Alternatively, a substrate may beadditionally disposed between the touch sensor 200 and the display panel300.

3. Display Panel

As schematically illustrated in FIG. 1, the display panel 300 has adisplay region 306 having a plurality of pixels 308 arranged in a rowdirection and a column direction. Wirings (not shown) extend from thedisplay region 306 to an edge portion of the array substrate 302 and areexposed at the edge portion of the array substrate 302 to form terminals314. The terminals 314 are connected to a connector such as a flexibleprinted circuit (FPC). Image signals supplied from an external circuitare transmitted to the pixels 308 through the terminals 314, and thedisplay elements in the pixels 308 are controlled in association withsignals from the driver circuits 310 and 312, thereby reproducing animage on the display region 306.

Display elements such as light-emitting elements or liquid crystalelements giving different colors can be disposed in the plurality ofpixels 308, by which full-color display is conducted. For example,display elements giving red, green, and blue colors may be arranged inthe respective pixels 308. Alternatively, display elements giving whitecolor may be used in all pixels 308, and red, green, and blue colors maybe extracted from the respective pixels 308 by using a color filter. Anarrangement of the pixels 308 is also not limited, and a stripearrangement, a delta arrangement, a Pentile arrangement, and the likemay be employed.

A schematic cross-sectional view of the display region 306 is shown inFIG. 8. FIG. 8 is a schematic view of a cross section of the pluralityof pixels 308 having light-emitting elements. A transistor 320 and alight-emitting element 350 connected to the transistor 320 are providedin each pixel 308. FIG. 8 shows an example in which one transistor 320is arranged in one pixel 308. However, a plurality of transistors may beprovided in one pixel 308, and other semiconductor elements such as acapacitor element may be arranged.

The transistor 320 may possess, over an undercoat 318 provided over thearray substrate 302 and consisting of one layer or a plurality oflayers, a semiconductor film 322, a gate insulating film 324, a gateelectrode 326, source/drain electrodes 330, and the like. An interlayerfilm 328 may be further formed over the gate electrode 326. There is nolimitation to the structure of the transistor 320, and a top-gate typetransistor or a bottom-gate type transistor may be used. A verticalrelationship between the semiconductor film 322 and the source/drainelectrodes 330 may be freely selected, and a bottom-contact type or atop-contact type may be employed.

A leveling film 340 absorbing projections, depressions, and inclinescaused by the transistor 320 and other semiconductor elements and givinga flat surface is provided over the transistor 320. A first electrode352 of the light-emitting element 350 is electrically connected to oneof the source/drain electrodes 330 through an opening portion formed inthe leveling film 340.

The display panel 300 further has a partition wall 342 covering an edgeportion of the first electrode 352 and filling the opening portion usedfor the connection between the first electrode 352 and one of thesource/drain electrodes 330. An EL layer 354 is disposed over the firstelectrode 352 and the partition wall 342 over which a second electrode362 is formed. In the present specification and claims, an EL layermeans layers sandwiched between the first electrode 352 and the secondelectrode 362. In FIG. 8, the EL layer 354 is illustrated so as to havethree layers (first layer 356, second layer 358, and third layer 360).However, the number of the layers in the EL layer 354 is not limited asdescribed below. The light-emitting element 350 is formed by the firstelectrode 352, the EL layer 354, and the second electrode 362.

A passivation film 370 for protecting the light-emitting element 350 isarranged over the light-emitting element 350. The passivation film 370has a function to prevent impurities such as water and oxygen fromentering the light-emitting element 350 from outside. As shown in FIG.8, the passivation film 370 may have a plurality of stacked layers.Here, the passivation film 370 has a first layer 372, a second layer374, and a third layer 376. As described below, the first layer 372 andthe second layer 376 may contain an inorganic compound, whereas thesecond layer 374 may include an organic compound. The opposing substrate304 is disposed over the passivation film 370 through an adhesion layer380.

As shown in FIG. 1, the touch sensor 200 is arranged under the displaypanel 300 in the display device 100 according to the present embodiment.Therefore, it is preferred that the display elements provided in thepixels 308 be configured so as to give an image on an upper side of thedisplay panel 300 through the opposing substrate 304. When the displayelement is a light-emitting element, the first electrode 352 and thesecond electrode 362 are configured so that light emitted from the ELlayer 354 is extracted through the second electrode 362.

As described above, the first layer 220 and the third layer 240 of thetouch sensor 200 are formed by weaving the plurality of insulators andwirings arranged in a stripe form. The second layer 230 may be alsoformed with a polymer usable in the first layer 220 and the third layer240. Hence, production of a flexible touch sensor 200 is also feasible.

Additionally, it is possible to prepare the first layer 220 and thethird layer 240 without a film-formation apparatus used in asemiconductor process, such as a sputtering apparatus and a CVDapparatus. Hence, there is no great necessity to apply a complicatedprocess such as a semiconductor process, and the touch sensor 200 can bemanufactured at low cost. Since a large-scale film-formation apparatusis not required, there is no great restriction on the size of the touchsensor 200. Therefore, the touch sensor 200 can be readily installed toa large-size display panel.

Second Embodiment

In the present embodiment, a touch sensor 400 with a structure differentfrom that of the touch sensor 200 described in the First Embodiment isexplained by using FIG. 9A and FIG. 9B. FIG. 9A is a schematic top viewof the touch sensor 400, and FIG. 9B is a schematic cross-sectional viewcorresponding to a chain line B-B′ of FIG. 9A. Explanation of thestructures the same as those of the First Embodiment may be omitted.

The touch sensor 400 is different from the touch sensor 200 in that ithas a single layer (first layer 404). Specifically, as shown in FIG. 9Aand FIG. 9B, the touch sensor 400 possesses the first layer 404 whichhas a plurality of first wirings 406 arranged in a stripe form and aplurality of second wirings 408 arranged in a stripe form. The firstwirings 406 and the second wirings 408 may be in contact with eachother. The plurality of first wirings 406 extends in a direction (firstdirection), whereas the plurality of second wirings 408 extends in adirection (second direction) perpendicular to the first direction. Thus,the plurality of first wirings 406 intersects with the plurality ofsecond wirings 408. The plurality of first wirings 406 and the pluralityof second wirings 408 are woven with each other. In FIG. 9A, the firstwirings 406 and the second wirings 408 are plain-woven. However, similarto the touch sensor 200, these wirings may be twilled or satin-woven.

Although not shown, similar to the First Embodiment, the display panel300 may be arranged over the first layer 404. In this case, the firstwirings 406 and the second wirings 408 may be in contact with the arraysubstrate 302.

At least one of the plurality of first wirings 406 and the plurality ofsecond wirings 408 has a bilayer structure. Specifically, as shown inFIG. 9B, at least one of these wirings has a core 410 and a clad 412covering the core 410. The core 410 contains a conductive materialrepresented by the materials usable for the first wirings 224 and thesecond wirings 242 of the First Embodiment.

On the other hand, the clad 412 surrounds the core 410 and includes aninsulating material. As an insulating material, the materials which canbe used for the first insulators 222 and the second insulators 244 ofthe First Embodiment are given.

A cross section of the core 410 is not limited in shape and may have avariety of shapes such as a circular shape, an elliptical shape, asquare shape, a rectangular shape, or a trapezoidal shape. The clad 412may be configured so that its cross-sectional shape is the same as,similar to, or different from that of the core 410. Note that a crosssection of the wirings may also have a variety of shapes. A horizontallylong shape or rectangular shape of the cross section of the wiringsprevents a lateral slide, by which detection accuracy of a touch can bestabilized. Additionally, the horizontally long shape enables athickness of the touch sensor to be reduced, maintaining sufficientsensitivity.

The clad 412 prevents a short circuit between the first wirings 406,between the second wirings 408, and between the first wiring 406 and thesecond wiring 408 and functions as a dielectric of capacitance formed atcross points of the first wirings 406 and the second wirings 408.Similar to the touch sensor 200, capacitance is generated at the crosspoints of the plurality of the first wirings 406 and the plurality ofsecond wirings 408. Hence, according to the same principle as that ofthe operation of the touch sensor 200, the touch sensor 400 is capableof specifying a touch position of a user.

In FIG. 9A and FIG. 9B, an example is demonstrated where the firstwirings 406 and the second wirings 408 both have the aforementionedbilayer structure. However, one of these wirings may not have thebilayer structure but may have a structure in which the core 410 isexposed. For example, one of these wirings may have the structure whichis the same as that of the first wiring 224 or the second wiring 242 ofthe touch sensor 200.

The present embodiment is able to not only provide the effects describedin the First Embodiment but also supply a touch sensor with a simplerstructure. Hence, it is possible to produce a touch sensor at lowercost. Moreover, a touch sensor thinner than the touch sensor 200 can beprovided. Accordingly, it is possible to further promote reduction inweight and thickness of a display device. Moreover, a display devicehaving higher flexibility can be produced.

Third Embodiment

In the present embodiment, a touch sensor 420 with a structure differentfrom those of the touch sensors 200 and 400 described in the First andSecond Embodiments is explained by using FIG. 11 to FIG. 14. FIG. 11 isa top view of the touch sensor 420, and the cross sections along chainlines C-C′, D-D′, and E-E′ correspond to FIG. 12A, FIG. 12B, and FIG.12C, respectively. Explanation of the structures the same as those ofthe First and Second Embodiments may be omitted.

As shown in FIG. 11, FIG. 12A, FIG. 12B, and FIG. 12C, the touch sensor420 possesses a single layer (first layer 424) similar to the touchsensor 400. The first layer 424 has a plurality of first wirings 426arranged in a stripe form, a plurality of second wirings 428 arranged ina stripe form, and a plurality of third wirings 430 arranged in a stripeform. The first wirings 426 and the second wirings 428 may be in contactwith each other, and the first wirings 426 and the third wirings 430 maybe also in contact with each other. The plurality of first wirings 426extends in a direction (first direction). On the other hand, theplurality of second wirings 428 and the plurality of third wirings 430extend in a direction (second direction) perpendicular to the firstdirection. Hence, the plurality of first wirings 426 intersects with theplurality of second wirings 428 and the plurality of third wirings 430.Note that the first direction and the second direction may not beperpendicular to each other as long as they intersect with each other.

Here, as shown in FIG. 11, the plurality of second wirings 428 and theplurality of third wirings 430 are arranged parallel so as to alternatewith each other, and one second wiring 428 other than those arranged atterminal positions is adjacent to and sandwiched by two third wirings430. Similarly, one third wiring 430 other than those arranged atterminal positions is adjacent to and sandwiched by two second wirings428. The plurality of first wirings 426 is woven with the plurality ofsecond wirings 428 and the plurality of third wirings 430. In FIG. 11,the first wirings 426 are plain-woven with the second wirings 428 andthe third wirings 430. However, similar to the touch sensor 200, thesewirings may be twilled or satin-woven.

Note that the number of the plurality of second wirings 428 and thenumber of the plurality of third wirings 430 may not be the same as eachother. Additionally, the plurality of second wirings 428 and theplurality of third wirings 430 may not be provided so as to alternatewith each other, and a multiple number of the plurality of third wirings430 may be disposed between two adjacent second wirings 428, forexample. Alternatively, a multiple number of the plurality of secondwirings 428 may be disposed between two adjacent third wirings 430.

Although not shown, similar to the Second Embodiment, the display panel300 may be arranged over the first layer 424. In this case, the firstwirings 426, the second wirings 428, and the third wirings 430 may be incontact with the array substrate 302.

Similar to the first wirings 406 and the second wirings 408 of the touchsensor 420, each of the plurality of first wirings 426 and each of theplurality of second wirings 428 have a bilayer structure. For example,as shown in FIG. 12A and its enlarged figure, the first wirings 406 andthe second wirings 408 each have a first core 432 and a first clad 434covering the first core 432. The first core 432 may include a conductivematerial represented by the materials usable for the first wirings 224and the second wirings 242 of the First Embodiment.

On the other hand, the first clad 434 surrounds the first core 432 andincludes an insulating material. As an insulating material, thematerials usable for the first insulators 222 and the second insulators244 of the First Embodiment are represented.

A shape of the cross section of the first core 432 is not limited, andthe cross section may have a variety of shapes similar to the firstwirings 406 and the second wirings 408 of the touch sensor 420. Forexample, as shown in FIG. 10, the first core 432 may have a variety ofcross-sectional shapes such as a circular shape, an elliptical shape, asquare shape, a rectangular shape, and a trapezoidal shape. The firstclad 434 may be also configured so that its cross-sectional shape is thesame as, similar to, or different from that of the first core 432.

The third wirings 430 have a three-layer structure. Specifically, asshown in FIG. 12B and FIG. 12C, the third wirings 430 each have a secondcore 436, a second clad 438 covering the second core 436, and a thirdclad 440 covering the second clad 438. The second core 436 may include aconductive material, and the materials usable in the first wirings 224and the second wirings 242 of the First Embodiment are represented as aconductive material.

The second clad 438 surrounds the second core 436 and includes aninsulating material. The materials usable in the first insulators 222and the second insulators 244 of the First Embodiment are represented asan insulating material. An elastomer may be also used as an insulatingmaterial and may have a property of being deformed when a pressure suchas a touch is applied and immediately returning to the original shapewhen the pressure is removed.

Here, the second clad 438 is configured to keep a distance between thethird clad 440 and the second core 436 in a normal direction (a pressingdirection) of the touch sensor 420 constant when a touch is notperformed. With this configuration, two functions as a capacitive-typetouch sensor and a pressure-sensitive touch sensor can be simultaneouslyrealized (details of operation principle are described below). This isbecause maintenance of a constant distance between the third clad 440and the second core 436 in the absence of a touch allows the capacitanceformed therebetween to be constant in the touch sensor 420 and to beutilized as a standard when a touch is not applied. Accordingly, a touchcan be correctly sensed.

Therefore, in the touch region 242, for example, a thickness of thesecond clad 438 may be adjusted to be entirely constant in the thirdwirings 430. Note that, in the touch region 242, a thickness of thefirst clad 434 may be also adjusted to be entirely constant in the firstwirings 426. Alternatively, the thickness of the first clad 434 of thefirst wirings 426 and the thickness of the second clad 438 of the thirdwirings 430 may be adjusted to be constant at the cross points of thefirst wiring 426 and the third wiring 430. Alternatively, the thicknessof the first clad 434 of the first wirings 426 may be adjusted to be thesame at least at the positions where the first wirings 426 and thesecond wirings 428 are in contact with each other, and the thickness ofthe first clad 438 of the second wirings 428 may be adjusted to be thesame at least at the position where the second wirings 428 and the firstwirings 426 are in contact with each other.

The third clad 440 surrounds the second clad 438 and may include aconductive material. The materials usable in the first wirings 224 andthe second wirings 242 of the First Embodiment are represented as aconductive material.

A cross section of the second core 436 is not limited in shape, and thesecond core 436 may have a variety of cross-sectional shapes such as acircular shape, an elliptical shape, a square shape, a rectangularshape, and a trapezoidal shape as shown in FIG. 13, for example. Thesecond clad 438 may be configured so that a cross-sectional shapethereof is the same as, similar to, or different from that of the secondcore 436. Similarly, the third clad 440 may be configured so that across-sectional shape thereof is the same as, similar to, or differentfrom those of the second core 436 and the second clad 438.

The function and operation of the touch sensor 420 are outlined by usingFIG. 14, FIG. 15A, and FIG. 15B. FIG. 14 is a drawing obtained byremoving the third wirings 430 from the first wirings 426, the secondwirings 428, and the third wirings 430 which construct the touch sensor420. As described above, the first wirings 426 and the second wirings428 each have the first core 432 including a conductive material and afirst clad 434 including an insulating material and covering the firstcore 432. The first clad 434 has a function to prevent a short circuitbetween the first wiring 426 and the second wiring 428 and a function asa dielectric of capacitance formed at the cross points of the firstwirings 426 and the second wirings 428. Similar to the touch sensor 200,capacitance 450 is generated at the cross points of the plurality offirst wirings and the plurality of second wirings. Hence, according to aprinciple the same as that of the touch sensor 200, the touch sensor 420is capable of specifying a touch position of a user. That is, acapacitive-type (projective-capacitive type) touch sensor is formed bythe first wirings 426 and the second wirings 428 of the touch sensor420.

FIG. 15A is a drawing obtained by removing the second wirings 428 fromthe first wirings 426, the second wirings 428, and the third wirings 430constructing the touch sensor 420, and FIG. 15B is a schematiccross-sectional view of the third wiring 430. As described above, thethird wirings 430 each have the second core 436 including a conductivematerial, the second clad 438 covering the second core 436 and includingan insulating material, and the third clad 440 covering the second clad438 and including a conductive material. Capacitance C represented byequation 1 is formed in the third wiring 430 with this structure:

$\begin{matrix}{C = \frac{2\pi \; ɛ\; L}{\ln ( {b\text{/}a} )}} & (1)\end{matrix}$

where C is a capacitance generated in the third wiring 430, ∈ is apermittivity of a material included in the second clad 438, L is alength of the third wiring 430 (in the second direction), a is a radiusof the cross section of the second core 436, and b is a radius of thesecond clad 438 when an outer circumference of the cross section of thesecond clad 438 is assumed to be circular (see FIG. 15B).

When a constant potential difference V is provided between the secondcore 436 and the third clad 440 of the third wiring 430, a chargecorresponding to the capacitance C is accumulated in the third wiring430. When a user applies a pressure by directly or indirectly contactingthe touch sensor 420 in this state, the second clad 438 is deformed.This is because an elastic modulus of the material used in the secondclad 438 is smaller than that in the second core 436, that is, becausethe material used in the second clad 438 is more flexible than that inthe second core 436. For example, as shown in FIG. 15B, when a pressureof a touch is applied from above to the third wiring 430, the secondclad 438 is deformed, leading to deformation of the third clad 440. As aresult, a thickness b significantly changes (b>b′), while a thickness anegligibly changes (a˜a′). Hence, the capacitance C of the third wiring430 changes according to the equation 1.

Accordingly, power consumption when charging and discharging the secondcore 436 or the third clad 440 changes in accordance with the change ofthe capacitance C. Sensing this change and its magnitude makes itpossible to sense a touch by a user and estimate intensity thereof.Furthermore, the third wirings 430 touched by a user can be specified.In other words, the third wirings 430 are capable of functioning as apressure-sensitive touch sensor.

In view of the aforementioned operation principle, it can be consideredthat the touch sensor 420 has a structure in which two kinds of touchsensors with different modes and functions, i.e., a capacitive touchsensor and a pressure-sensitive touch sensor, are constructed in thesame layer. Hence, application of the present embodiment provides notonly the effects described in the First and Second Embodiments but alsoenables production of a touch sensor having two functions as a singlelayer. Accordingly, it is possible to produce a display device which ishighly functionalized and reduced in weight and thickness.

Fourth Embodiment

In the present embodiment, a touch sensor 460 with a structure differentfrom those of the touch sensors 200, 400, and 420 is explained by usingFIG. 16 to FIG. 18B. FIG. 16 is a schematic top view of the touch sensor460, and FIG. 18A is a schematic cross-sectional view along a chain lineF-F′ of FIG. 16.

Similar to the touch sensor 200, the touch sensor 460 has a first layer470, a second layer 484 over the first layer 470, and a third layer 490over the second layer 484. In FIG. 16, only the second layer 484 and thethird layer 490 are shown for promoting understanding. The first layer470, the second layer 484, and the third layer 490 may havesubstantially the same shape and size and overlap with one another.

The first layer 470, the second layer 484, and the third layer 490obtained by developing the touch sensor 460 are shown in FIG. 17A, FIG.17B, and FIG. 17C, respectively. As shown in FIG. 17A, the first layer470 possesses a plurality of first insulators 472 arranged in a stripeform and a plurality of first wirings 474 arranged in a stripe form. Thefirst insulators 472 and the first wirings 474 may be in contact witheach other. The first insulators 472 extend in a direction (firstdirection), whereas the first wirings 474 extends in a direction (seconddirection) perpendicular to the first direction. The first insulators472 and the first wirings 474 are woven with each other and serve aswarp and weft, respectively. As shown in FIG. 17A, the first insulators472 and the first wirings 474 may have a structure in which they areplain-woven. However, they may be twilled or satin-woven.

The second layer 484 is provided over the first layer 470. The secondlayer 484 may be in contact with the first wirings 474 and the firstinsulators 472. The second layer 484 may have the same structure as thatof the second layer 230 of the touch sensor 200 described in the FirstEmbodiment.

The third layer 490 may have a similar structure to that of the firstlayer 470. Specifically, as shown in FIG. 17C, the third layer 490 has aplurality of second wirings 492 arranged in a stripe form and aplurality of second insulators 494 arranged in a stripe form. The secondwirings 492 and the second insulators 494 may be in contact with eachother. The second wirings 492 and the second insulators 494 may be incontact with the second layer 484. The second wirings 492 extend in thefirst direction, whereas the second insulators 494 extend in the seconddirection. Therefore, the plurality of first wirings 474 and theplurality of second wirings 492 intersect with each other with thesecond layer 484 sandwiched therebetween. The second wirings 492 and thesecond insulators 494 are woven with each other and sever as warp andweft, respectively. As shown in FIG. 17C, the second wirings 492 and thesecond insulators 494 may have a structure in which they areplain-woven. However, they may be twilled or satin-woven.

As shown in FIG. 18A and FIG. 18B, similar to the first wirings 406 andthe second wirings 408 of the touch sensor 400, each of the firstwirings 474 may have a bilayer structure. That is, the plurality offirst wirings 474 each possess a first core 476 and a first clad 478covering the first core 476. The first core 476 may include a conductivematerial, and the materials usable for the first wirings 224 and thesecond wirings 242 of the First Embodiment are represented as aconductive material.

The first clad 478 surrounds the first core 476 and includes aninsulating material. The materials usable in the first insulators 222and the second insulators 244 of the First Embodiment are exemplified asan insulating material.

Similar to the third wirings 430 of the touch sensor 420, each of theplurality of the second wirings 492 may have a three-layer structure.Specifically, as shown in FIG. 18A and FIG. 18B, the second wirings 492each have a second core 496, a second clad 498 covering the second core496, and a third clad 500 covering the second clad 498. The second core496 may include a conductive material, and the materials usable for thefirst wirings 224 and the second wirings 242 of the First Embodiment arerepresented as a conductive material.

The second clad 498 surrounds the second core 496 and includes aninsulating material. The materials usable for the first insulators 222and the second insulators 244 of the First Embodiment are represented asan insulating material. As an insulating material, an elastomer which isdeformed when a pressure is applied and immediately returns to theoriginal shape when the pressure is removed is preferred.

The third clad 500 surrounds the second clad 498 and may include aconductive material. The materials usable for the first wirings 224 andthe second wirings 242 of the First Embodiment are exemplified as aconductive material.

Similar to the first wirings 406 and the second wirings 408 of the touchsensor 400 and the third wirings 430 of the touch sensor 420,cross-sectional shapes of the first wirings 474 and the second wirings492 of the touch sensor 460 are freely designed and may be the shapesillustrated in FIG. 10 and FIG. 13, respectively.

As described above, the plurality of the first wirings 474 and theplurality of second wirings 492 perpendicularly intersect with eachother with the second layer 484 containing an insulating materialsandwiched therebetween. Therefore, the second layer 484 functions as adielectric, and capacitance is formed at the cross points of theplurality of first wirings 474 and the plurality of second wirings 492.According to the principle the same as that of the touch sensor 200, thetouch sensor 460 is capable of specifying a touch position of a user.

In contrast, similar to the third wirings 430 of the touch sensor 420,the second wirings 492 in the third layer 490 of the touch sensor 460have a capacitance C represented by the equation 1. Additionally, thesecond clad 498 is deformed due to the material used therein when a userapplies a pressure by directly or indirectly touching the touch sensor460. As a result, the capacitance between the second core 496 and thethird clad 500 is changed, and power consumption when charging anddischarging the second core 496 or the third clad 500 is changed.Sensing of this change and intensity thereof allows sensing a touch by auser and estimating its intensity. Moreover, the second wirings 492touched by a user can be specified. Namely, the second wirings 492 arecapable of functioning as a pressure-sensitive touch sensor. In view ofthe aforementioned operation principle, it can be concluded that thetouch sensor 460 has a structure in which two kinds of touch sensorswith different modes and functions are stacked.

The first layer 470 and the third layer 490 of the touch sensor 460 maybe interchanged with each other. That is, as shown in FIG. 19, the touchsensor 460 may include the third layer 490 in which the second wirings492 and the second insulators 494 are woven with each other.Furthermore, the first layer 470 in which the first insulators 472 andthe first wirings 474 are woven may be provided over the third layer 490with the second layer 484 sandwiched therebetween.

Similar to the touch sensor 200 and the like, a film-formation apparatusused in a semiconductor process, such as a sputtering apparatus and aCVD apparatus, is not necessary in manufacturing the touch sensor 460.Therefore, there is a low necessity to apply a complicated process likea semiconductor process, and the touch sensor 460 can be manufactured inlow cost. Moreover, since a large-scale film-formation apparatus is notrequired, there is no great restriction on the size of the touch sensor460. Therefore, the touch sensor 200 can be readily installed to alarge-size display panel.

Fifth Embodiment

In the present embodiment, an example of a method for manufacturing thedisplay panel 300 described in the First Embodiment is explained byusing FIG. 8 and FIG. 20A to FIG. 22B. FIG. 20A to FIG. 22B correspondto the cross-sectional view of FIG. 8. Explanation of the structures thesame as those of the First Embodiment may be omitted.

First, the undercoat 318 is formed over the array substrate 302 (FIG.20A). The array substrate 302 has a function to support thesemiconductor elements included in the display panel 300, such as thetransistor 320 and the light-emitting element 350. The array substrate302 may contain glass, plastics, a metal, or the like. The arraysubstrate 302 may have flexibility. In this case, the array substrate302 may include a polymer such as a polyimide, a polyester, and apolycarbonate.

The undercoat 318 is a film having a function to prevent diffusion ofimpurities such as an alkaline metal from the array substrate 302 to thetransistor 320 and the like and may include an inorganic insulator suchas silicon nitride, silicon oxide, silicon nitride oxide, and siliconoxynitride. The undercoat 318 can be formed with a CVD method, asputtering method, or the like so as to have a single layer or stackedlayer structure. When an impurity concentration in the array substrate302 is low, the undercoat may not be provided or may be provided topartly cover the array substrate 302.

Next, the semiconductor film 322 is formed over the undercoat 318 (FIG.20A). The semiconductor film 322 may include a Group 14 element such assilicon, for example. Alternatively, the semiconductor film 322 mayinclude an oxide semiconductor. An oxide semiconductor may contain aGroup 13 element such as indium and gallium and is exemplified by amixed oxide of indium and gallium (IGO). When an oxide semiconductor isused, the semiconductor film 322 may further contain a Group 12 element,and a mixed oxide including indium, gallium, and zinc (IGZO) isrepresented as an example. Crystallinity of the semiconductor film 322is not limited and may be single-crystalline, polycrystalline,microcrystalline, or amorphous.

When the semiconductor film 322 includes silicon, the semiconductor film322 may be formed with a CVD method by using a silane gas or the like asa raw material. Crystallization may be conducted on the obtainedamorphous silicon by performing a heat treatment or irradiation of lightsuch as a laser. When the semiconductor film 322 includes an oxidesemiconductor, the semiconductor film 322 can be prepared by utilizing asputtering method and the like.

Next, the gate insulating film 324 is formed so as to cover thesemiconductor film 322 (FIG. 20A). The gate insulating film 324 may havea single-layer structure or a stacked-layer structure and can be formedwith a method the same as that of the undercoat 318. Alternatively, aninorganic compound with high permittivity, such as hafnium oxide andhafnium silicate, may be used.

Next, the gate electrode 326 is formed over the gate insulating film 324with a sputtering method or a CVD method (FIG. 20B). The gate electrode326 can be formed with a metal such as titanium, aluminum, copper,molybdenum, tungsten, and tantalum or an alloy thereof so as to have asingle-layer or stacked layer structure. For example, a structure can beemployed in which a metal with a high conductivity, such as aluminum andcopper, is sandwiched by a metal with a relatively high melting point,such as titanium, tungsten, and molybdenum.

Next, the interlayer film 328 is fabricated over the gate electrode 326(FIG. 20B). The interlayer film 328 may have a single-layer structure ora stacked-layer structure and can be formed with a method the same asthat of the undercoat 318.

Next, etching is performed on the interlayer film 328 and the gateinsulating film 324 to form an opening portion reaching thesemiconductor film 322. The opening portion may be formed by conductingplasma etching in a gas including a fluorine-containing hydrocarbon, forexample. Sequentially, a metal film is formed so as to cover the openingportion and processed by etching, thereby forming the source/drainelectrodes 330 (FIG. 20C). The metal film may have a similar structureto that of the gate electrode 326 and can be formed with a methodsimilar to that of the gate electrode 326. Through these steps, thetransistor 320 is fabricated.

Next, the leveling film 340 is formed to cover the source/drainelectrodes 330 (FIG. 21A). As described above, the leveling film has afunction to absorb projections, depressions, and inclinations caused bythe transistor 320 and other semiconductor elements and to give a flatsurface. The leveling film 340 can be formed with an organic compound.As an organic compound, a polymer material such as an epoxy resin, anacrylic resin, a polyimide, a polyamide, a polyester, a polycarbonate,and a polysiloxane is exemplified, and the leveling film 340 can beformed with a wet-type film-formation method. The leveling film 340 mayhave a stacked structure including a layer containing the aforementionedorganic compound and a layer containing an inorganic compound. In thiscase, a silicon-containing inorganic compound such as silicon oxide,silicon nitride, silicon nitride oxide, and silicon oxynitride isrepresented as an inorganic compound. A film containing these inorganiccompounds may be formed with a sputtering method or a CVD method.

Next, etching is carried out on the leveling film 340 to form theopening reaching one of the source/drain electrodes 330. After that, thefirst electrode 352 of the light-emitting element 350 is formed over theleveling film 340 by using a sputtering method and the like (FIG. 21B).In the present embodiment, a structure is shown in which the firstelectrode 352 is in direct contact with the source/drain electrode 330.However, another layer with conductivity may be formed between the firstelectrode 352 and the source/drain electrode 330.

The first electrode 352 may include a conductive oxide with alight-transmitting property or a metal. In the present embodiment, ametal such as aluminum and silver or an alloy thereof may be used forthe first electrode 352 in order to extract light obtained from thelight-emitting element 350 in a direction opposite to the arraysubstrate 302. In this case, a stacked structure of the aforementionedmetal or alloy and a conductive oxide having a light-transmittingproperty, i.e., a stacked structure in which a metal is sandwiched by aconductive oxide (conductive oxide/metal/conductive oxide), may beemployed. As a conductive oxide, indium-tin oxide (ITO) or indium-zincoxide (IZO) can be used.

Next, the partition wall 342 is fabricated to cover the edge portion ofthe first electrode 352 (FIG. 21B). A step caused by the first electrode352 and the like can be covered with the partition wall 342. Thepartition wall 342 is also an insulating film and can be formed with awet-type film-formation method by using a material usable for theleveling film 340, such as an epoxy resin and an acrylic resin.

Next, the light-emitting element 350 is prepared. Specifically, the ELlayer 354 is formed over the first electrode 352 and the partition wall342 (FIG. 22A). In FIG. 22A, the EL layer 354 has a three-layerstructure including the first layer 356, the second layer 358, and thethird layer 360. However, a structure of the EL layer 354 is notlimited. The EL layer 354 may be formed with a single layer or four ormore layers. For example, the EL layer 354 can be prepared byappropriately combining a carrier-injection layer, acarrier-transporting layer, an emission layer, a carrier-blocking layer,an exciton-blocking layer, and the like. The EL layer 354 can be formedwith the aforementioned wet-type film-formation method, an evaporationmethod, or the like.

In FIG. 22A, an example is shown in which the first layer 356 and thethird layer 360 are continuously formed between the adjacent pixels 308,while the second layer 358 are independently formed between the adjacentpixels 308. However, the structure of the EL layer 354 is not limitedthereto. For example, the EL layer 354 with the same structure may beused in all of the pixels 308. In this case, the EL layer 354 givingwhite emission is formed so as to be shared by the adjacent pixels 308,and a wavelength of light extracted from each pixel 308 is selected witha color filter and the like. Alternatively, the structure of the ELlayer 354 may be different between the adjacent pixels 308. For example,the EL layer 354 may be formed so that the emission layer is differentbut other layers have the same structure between the adjacent pixels308.

The light-emitting element 350 is fabricated by forming the secondelectrode 362 over the EL layer 354 (FIG. 22A). For example, the secondelectrode 362 can be formed by preparing a film of a metal such asmagnesium and silver or an alloy thereof at a thickness which permitsvisible light to pass therethrough. Alternatively, the second electrode362 may be formed by using a conductive oxide transmitting visiblelight, such as ITO and IZO, with a sputtering method and the like. Withthis structure, the emission from the EL layer 354 can be extractedthrough the second electrode 362.

Next, the passivation film 370 is formed over the light-emitting element350 (FIG. 22B). As shown in FIG. 22B, the passivation film 370 maypossess a three-layer structure, for example. Such a structure can beformed as follows. First, the first layer 372 is formed over the secondelectrode 362. The first layer 372 may include an inorganic compoundsuch as silicon nitride, silicon oxide, silicon nitride oxide, andsilicon oxynitride and can be formed with a method the same as that ofthe undercoat 318. Sequentially, the second layer 374 is formed. Thesecond layer 374 may contain an organic resin including an acrylicresin, a polysiloxane, a polyimide, or a polyester. Furthermore, asshown in FIG. 22B, the second layer 374 may be formed so as to have athickness which absorbs projections and depressions caused by thepartition wall 342 and provides a flat surface. The second layer 374 canbe formed with the aforementioned wet-type film-formation method.Alternatively, the second layer 374 may be formed by atomizing orgasifying oligomers serving as a raw material of the aforementionedpolymers under a reduced pressure, spraying the first layer 372 with theoligomers, and then polymerizing the oligomers. After that, the thirdlayer 376 is formed (FIG. 22B). The third layer 376 may have thestructure which is the same as that of the first layer 372 and can beformed with the method which is the same as that of the first layer 372.

The passivation film 370 having such a structure exhibits a highgas-barrier property, by which entrance of impurities such as water andoxygen to the light-emitting element 350 can be prevented and highreliability can be provided to the display panel 300.

After that, the opposing substrate 304 is fixed over the passivationfilm 370 by using the adhesion layer 380 (FIG. 8). An epoxy resin andthe like can be used for the adhesion layer 380. Through theseprocesses, the display panel 300 is prepared.

After that, as described in the Second Embodiment, the display device100 is manufactured by fixing the display panel 300 over the touchsensor 200 (FIG. 7).

The aforementioned modes described as the embodiments of the presentinvention can be implemented by appropriately combining with each otheras long as no contradiction is caused. Furthermore, any mode which isrealized by persons ordinarily skilled in the art through theappropriate addition, deletion, or design change of elements or throughthe addition, deletion, or condition change of a process is included inthe scope of the present invention as long as they possess the conceptof the present invention.

In the specification, although cases of the organic EL display deviceare exemplified, the embodiments can be applied to any kind of displaydevices of the flat panel type such as other self-emission type displaydevices, liquid crystal display devices, and electronic paper typedisplay device having electrophoretic elements and the like. Inaddition, it is apparent that the size of the display device is notlimited, and the embodiment can be applied to display devices having anysize from medium to large.

It is properly understood that another effect different from thatprovided by the modes of the aforementioned embodiments is achieved bythe present invention if the effect is obvious from the description inthe specification or readily conceived by persons ordinarily skilled inthe art.

What is claimed is:
 1. A touch sensor comprising: a first layerincluding: a plurality of first insulators arranged in a stripe form andextending in a first direction; and a plurality of first wiringsarranged in a stripe form and extending in a second directionintersecting with the first direction; a second layer over the firstlayer, the second layer including an insulating material; and a thirdlayer over the second layer, the third layer including: a plurality ofsecond insulators arranged in a stripe form and extending in the seconddirection; and a plurality of second wirings arranged in a stripe formand extending in the first direction, wherein the plurality of firstinsulators and the plurality of the first wirings are woven with eachother, and the plurality of second insulators and the plurality of thesecond wirings are woven with each other.
 2. The touch sensor accordingto claim 1, wherein: the plurality of first wirings each comprises: afirst core including a conductive material; a first clad covering thefirst core and including an insulating material; and a second cladcovering the first clad and including a conductive material; and theplurality of second wirings each comprises: a second core including aconductive material; and a third clad covering the second core andincluding an insulating material.
 3. The touch sensor according to claim2, wherein: a thickness of the first clad of the first wirings is thesame at least at positions in which the first wirings intersect with thesecond wirings; and a thickness of the second clad of the second wiringsis the same at least at the positions.
 4. The touch sensor according toclaim 2, wherein the insulating material of the first clad is anelastomer.
 5. The touch sensor according to claim 1, wherein: theplurality of first wirings each comprises: a first core including aconductive material; and a first clad covering the first core andincluding an insulating material; and the plurality of second wiringseach comprises: a second core including a conductive material; a secondclad covering the second core and including an insulating material; anda third clad covering the second clad and including a conductivematerial.
 6. The touch sensor according to claim 5, wherein theinsulating material of the second clad is an elastomer.
 7. The touchsensor according to claim 1, wherein: the plurality of first insulatorsand the plurality of the first wirings are plain-woven, twilled, orstain-woven; and the plurality of the second insulators and theplurality of the second wirings are plain-woven, twilled, orstain-woven.
 8. The touch sensor according to claim 2, wherein: across-sectional shape of the first wirings is circular, elliptical,square, or trapezoidal, and a cross-sectional shape of the secondwirings is circular, elliptical, square, or trapezoidal.
 9. The touchsensor according to claim 2, wherein: a cross-sectional shape of thefirst core is circular, elliptical, square, or trapezoidal, and across-sectional shape of the second core is circular, elliptical,square, or trapezoidal.
 10. A display device comprising: a displaypanel; and the touch sensor according to claim
 1. 11. A touch sensorcomprising: a plurality of first wirings arranged in a stripe form andextending in a first direction; and a plurality of second wiringsarranged in a stripe form and extending in a second directionintersecting with the first direction, wherein the plurality of firstwirings and the plurality of second wirings are woven with each other,the plurality of first wirings and the plurality of the second wiringseach comprises: a first core including a conductive material; and a cladcovering the core and including an insulating material.
 12. The touchsensor according to claim 11, wherein: a thickness of the clad of thefirst wirings is the same at least at positions in which the firstwirings are in contact with the second wirings; and a thickness of theclad of the second wirings is the same at least at the positions. 13.The touch sensor according to claim 11, wherein the plurality of firstwirings and the plurality of second wirings are plain-woven, twilled, orstain-woven.
 14. The touch sensor according to claim 11, wherein across-sectional shape of the core is circular, elliptical, square, ortrapezoidal.
 15. A display device comprising: a display panel; and thetouch sensor according to claim
 11. 16. A touch sensor comprising: aplurality of first wirings arranged in a stripe shape and extending in afirst direction; and a plurality of second wirings and a plurality ofthird wirings arranged in a stripe shape, extending in a seconddirection, and alternating with each other, wherein the plurality offirst wirings are woven with the plurality of second wirings and theplurality of third wirings, the plurality of first wirings and theplurality of second wirings comprise: a first core including aconductive material; and a first clad covering the first core andincluding an insulating material, and the plurality of third wiringscomprises: a second core including a conductive material; a second cladcovering the second core and including an insulating material; and athird clad covering the second clad and including a conductive material.17. The touch sensor according to claim 16, wherein the insulatingmaterial of the second core is an elastomer.
 18. The touch sensoraccording to claim 16, wherein: a cross-sectional shape of the firstcore is circular, elliptical, square, or trapezoidal, and across-sectional shape of the second core is circular, elliptical,square, or trapezoidal.
 19. The touch sensor according to claim 16,wherein the plurality of first wirings are plain-woven, twilled, orstain-woven with the plurality of second wirings and the plurality ofthird wirings.
 20. A display device comprising: a display panel; and thetouch sensor according to claim 16.